Porous electrodes containing catalytic particulates have been developed to enhance the commercialization of electrolytic devices such as fuel cells and metal-air batteries. The electrodes can be useful as oxygen cathodes in such batteries and fuel cells. To enhance their commercial potential, efforts have been extended to augment the electrode capability to operate at high current densities coupled with acceptable durability.
Attention has also been paid to the development of efficient and economical electrodes capable of performing in the harsh chemical environments created by acid or alkaline electrolytes. It has been necessary to attempt to maintain a balance for the permeability of the liquid electrolyte and for the gaseous reactant. Progress in electrode development has led to, for example, electrodes capable of sustained performance at current densities substantially above about 400 milliamps per square centimeter, while exhibiting acceptable resistance to electrolyte. However, long operating life with sustained, desirable performance including resistance to electrode flooding while retarding undesirable depletion of catalytic activity is still needed.